by doing; in doing ;on doing 的意思这三个词组的意思

by doing by doing; in doing ;on doing 的意思这三个词组的意思 learn by doing. 是什么意思? learning by doing Learn by doing “by doing this one make it possible by doing sth造句make a contribution to doing sthThere be sb/sth doing sthThank sb for doing sth What about doing sth?spend+Time+(in)doing sth be expert at doing 还是in doing practice in doing 和practice doing 区别 spend in doing还是 on doing have fun in doing absorb sb in doing interest in doing something be occupied in doing waste time in doing doing business in be behind in doing involve in doing